Hello,

I am looking for any help in clarifying if I am on the right track, or help to put me on the right track. There is only 1 question with my answers for now, and I would really appreciate any input.

Thank you in advance!

Also for the question I have:

-stated the null and alternative hypothesis

-stated the critical region to reject or fail to reject the null

-Identified the test stat

-found the test stat

-stated the conclusion.

The question:

A customer is in need of a large supply of copper tubing that is cut 1.25 meters long. A plumbing supply company guarantees that if you order a specified lenght, you will receive what you ordered within a standard deviation=0.0001. To test the companies guarantee, a sample of 10 pieces of the tubing was taken. The mean length of the tubing was 1.2502 meters. Assume the population is normally distributed.

a)Is there a significant difference in the specified length of the tubing at the 0.01 significance level? Based on your answer, should the customer trust the guarantee?

b)Calculate the p-value at the 0.01 significance level. Is it significant?

My answers:

Ho: u=1.25 H1: u=/=1.25

Critical region: Fail to reject Ho if the test statistic falls between 2.33 and -2.33. Reject Ho if the test statistic does not fall between 2.33 and -2.33.

z=6.3 with test stat=0.0001

Conclusion: There is not sufficient sample evidence to warrant rejection of the claim that if you order a specified length of pipe, you will receive it within a standard deviation of 0.0001.

a)No, there is not a significant difference in the length of tubing at the 0.01 significance level. The customer should trust the company's guarantee.

b) P-value=0.0002 and it is not significant.